Using the Sum and Difference Identities, I do examples of evaluating trigonometric expressions that require the use of the sum and difference identities for sine, cosine, and tangent.

At the end of the example of sin(195) I say the denominator of the answer is 2 but 2*2 equals 4. Sorry for the error. There is an annotation correction, but you will not see it if you do not have Flash.

Check out http://www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. Find free review test, useful notes and more at http://www.mathplane.com

Tagged under: sum,difference,identity,identities,evaluate,trig,trigonometric,expressions,sin,cosine,tangent,tarrou,tarrou',chalk,talk,profrobbob,precalculus,trigonometry,math,education,examples

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